Resistive heating elements provide a simple and economically practical means for generating heat in a wide variety of situations. For example, devices as diverse as those employed in the home appliance field, the industrial equipment field and the medical/surgical instrument field all utilize resistive heating elements to achieve or maintain desired temperatures under varying conditions. In some applications, such as home heating systems, relatively gross temperature control over the resistive heating element is sufficient to satisfy temperature demands. Other applications, such as those involving the use of hemostatic scalpel blades during surgical operations, require precise control over resistive heating element temperatures if the resistive heating element is to be successfully operated. It is with this latter category of applications that the controller of the present invention is concerned.